Re: [Haskell-cafe] ANN: unordered-containers - a new, faster hashing-based containers library

On 20 February 2011 03:40, Louis Wasserman wrote:

I'd like to complain about that, too ;)

I'm curious, when do people find that they need a really fast way to get map size? I use them quite a lot, and almost never call length - and when I do, it is typically only to get some statistics about the map for user display - certainly not in an inner loop. I find it is still useful to have a way to quickly test if a map is empty (for e.g. fixed points that slowly grow a map by unioning in a new bit every time) but "null" works OK for that purpose. Cheers, Max